共查询到20条相似文献,搜索用时 15 毫秒
1.
在分析单层和多层衍射元件衍射效率的基础上,推导出光学系统中多层衍射元件浮雕深度和基底材料的一般关系式,并对这些变量进行优化,得到阿贝数的值大致在20~80之间,β的合理值在0.25~0.6之间,当2个衍射元件的阿贝数v1<v2,且差值比较大时,阿贝数小的衍射元件的基底材料选择光学玻璃中的火石玻璃,阿贝数大的衍射元件的基底材料选择光学玻璃中的冕牌玻璃。根据这个方法,设计了3组可实现宽波段高衍射效率的不同材料、不同浮雕深度的组合,使得每组组合中两层衍射元件的衍射效率都在99%以上。 相似文献
2.
In industrial processes using fibre beam delivery of high peak power laser light, diffractive optical elements are a very useful and flexible tool in maximising the amount of light reaching the work surface. This is due to the ability of diffractive optical elements to accurately couple light into multiple fibres, while conditioning the light in order to maximise the throughput for each fibre. We discuss the design techniques for diffractive optical elements and the application of these techniques to fibre-coupling problems. The flexibility of diffractive optical elements is demonstrated by their application to several fibre-coupling geometries, including a fibre bundle, a linear array of fibres, and a rotationally symmetric fibre connector. The diffraction efficiencies for the elements approach 90% with uniformity errors of less than 5%. 相似文献
3.
The application of electron-beam lithography to the generation of diffractive optical elements topology is examined. The formula for the estimation of exposure data volume for variable-shaped electron-beam lithography is presented as a function of diffractive optical element parameters and approximation accuracy. A special software dedicated to preparing exposure data for fabrication of diffractive optical elements is developed. Diffractive optical elements with an artificial refractive index are manufactured with a feature size much less than the wavelength. Design and experimental results on photomasks fabrication for an optical element focusing radiation into a ring with pregiven parameters are presented. The photomask set is manufactured for a reflecting optical element focusing the high power CO2 laser beam into two points with required parameters for laser welding. 相似文献
4.
This paper presents methods for designing and recording optimal computer-generated diffractive optical elements. The design method is based on an analytic ray-tracing procedure for minimizing aberrations. The recording involves computer-generated masks and multiple lithographic processes in order to form reflective and transmissive multilevel, surface relief-phase, diffractive elements. As a result, the elements can have high diffraction efficiencies over a broad range of incidence angles. Even generalized diffractive elements that operate with highly uniform diffraction efficiency and polychromatic radiation can be designed and recorded by optimizing the shape and height of the relief gratings. To illustrate the effectiveness of the diffractive optical elements, they have been incorporated into a number of applications, involving visible as well as infra-red radiation. Some that deal with coordinate transformation, beam shaping, and polarization control are briefly reviewed. 相似文献
5.
Debashis Chanda Ladan E. Abolghasemi Peter R. Herman 《Applied Physics A: Materials Science & Processing》2008,93(1):33-37
Phase tunable multi-level diffractive optical elements define an attractive approach for single laser exposure fabrication
of 3-dimensional photonic crystal microstructures. The significant advantage of these multi-level diffractive optical elements
over two-level diffractive optical elements is the flexibility of fabricating a wide range of 3-dimensional periodic structures
by manipulating the relative phase of different diffracted beams. Here, phase tuning was applied to demonstrate fabrication
of a hybrid 3-dimensional structure intermediate between previously reported diamond-like Woodpile-type structure of tetragonal
symmetry and structure having body-centered-tetragonal lattice symmetry. Circularly polarized light was applied for the first
time to balance the diffraction order efficiencies and improve the structural uniformity. Design guidelines are presented
for generating diamond-like photonic crystal template that possesses complete photonic bandgap when inverted with high refractive
index materials. 相似文献
6.
利用二维杨-顾算法设计非对称结构衍射光学元件 总被引:1,自引:0,他引:1
杨 顾算法是一种设计衍射光学元件的相位恢复方法。在大多数文献中,主要用它来设计一维衍射光学元件和具有旋转对称结构的二维衍射光学元件,故在此称之为一维杨 顾算法。二维杨 顾算法可用来设计任意结构的二维衍射光学元件。在基于非幺正变换光学系统中,用振幅 相位恢复理论建立了二维杨 顾算法的数学模型,给出了迭代算法。利用自编的仿真程序包设计了一个具有非对称结构的衍射相位元件。 相似文献
7.
在折衍混合光学系统的加工和装配过程中,折、衍器件间的对中精度严重影响混合器件的质量和性能,但是由于衍射器件与传统折射器件的显着差异,传统的对中手段已不再适用,如何简便实现二者的精确对中是混合光学系统实用化过程中亟待解决的问题之一.本文提出利用干涉原理简便地实现衍射器件与折射器件的高精度对中,理论分析和实验结果表明该对中装校方法是有效可行的,可以满足光学系统的对中要求。 相似文献
8.
The efficiency of conventional diffractive optical elements with échelette-type profiles drops rapidly as the illumination wavelength departs from the blaze wavelength. We use high dispersion of artificial materials to synthesize diffractive optical elements that are blazed over a broad spectral range (approximately 1 octave) or for two different wavelengths. 相似文献
9.
非制冷长波红外热像仪折衍混合双视场光学系统设计 总被引:1,自引:0,他引:1
根据衍射光学元件具有大的负向色散特性,将衍射光学元件应用于红外双视场光学系统中,根据傅里叶光学分析衍射光学元件(DOE)的消色差,列表对比折射透镜与衍射光学透镜的特性,并给出变倍比为4∶1可用作非制冷红外热像仪的光学系统的具体设计实例.系统采用切入式变焦方式,在短焦时切入2片透镜实现宽视场,通过引入二元面和非球面提高了成像质量.设计结果表明:在空间频率11 lp/mm处,短焦距40 mm时,各个视场的MTF值均大于0.6;长焦距160 mm时,各个视场的MTF值均大于0.7,宽视场和窄视场都具有较好的成像质量. 相似文献
10.
11.
12.
13.
14.
We present an optimization algorithm for the design of multilevel diffractive optical elements in the electromagnetic domain. The method uses the wavelet transform to parameterize the diffractive optical elements according to a set of coefficients that corresponds to a multiresolution basis. Both local and global optimizations can be performed within a single algorithm. A design example consisting of the optimization of a two-dimensional millimeter-wave diffractive lens over a 10% bandwidth is presented. 相似文献
15.
ZHAO Liping WU Minxian MAO Wenwei JIN Guofan YAN Yingbai 《Chinese Journal of Lasers》1998,7(5):413-418
1IntroductionWiththedevelopmentoftheintegratedopticsandfabricationtechnologyofsemiconductor,opticalFouriertransform(OFT)isbec... 相似文献
16.
17.
18.
用于衍射光学元件优化设计的遗传算法及其与模拟退火算法的比较 总被引:7,自引:1,他引:6
本文成功地将遗传算法运用于高维衍射位相光学元件的优化设计.并与模拟退火算法进行了比较.结果表明,该算法不仅对于二元,而且对于多元位相光学元件的优化疫计均是十分有效的.而且,它特别适用于利用光电混合处理系统进行优化计算. 相似文献
19.
20.
衍射光学元件衍射效率的测量 总被引:2,自引:0,他引:2
根据衍射光学元件衍射效率的测量原理,建立衍射光学元件衍射效率测量的双光路装置,简要介绍了双光路测量的优点。针对衍射光学元件衍射效率的测量装置,讨论了影响衍射效率测量精度的因素,合理地选择测量装置中的针孔光阑,即可以让主衍射级次的光全部通过被探测器接收,又可以滤掉次级衍射光,保证测量结果的准确度。针对所设计研制的一个折衍射混合成像光学系统,测量了可见光波段3个激光波长的衍射效率,并对测量结果进行了模拟和分析。在473~632.8nm波段范围内任意一个波长处,衍射效率的测量结果同理论值的偏差均小于5.0%。实验证明,双光路测量装置可以用于测量衍射光学元件的衍射效率。 相似文献